Occasional ContributorHello everyone,
Recently, I want to use the Emulated LVDS output on Arria V device. But I have no idea how to implement it ? Just to use Altera_tx IP + ALTIOBUF IP + Output Resistor Network? I have try once using the method, but It has error. Who can provide me one example about Emulated LVDS output buffer ?
Best regards,
Lambert
Frequent ContributorHi Lambert,
Kindly find the transcript from the user guide to perform Emulated LVDS OUTPUT buffers .
Emulated LVDS Buffers in Arria V Devices The Arria V device family supports emulated LVDS: • You can use unutilized true LVDS input channels as emulated LVDS output buffers (eTX) for serializa‐ tion factors of 1 and 2. • The emulated differential output buffers support tri-state capability
Occasional ContributorHi RSree,
I have read that you said "Emulated LVDS Buffers In Arria V Device Handbook " previously. And I tried to use ALTLVDS_TX IP + ALTIOBUF + External resistor network to implement eTX.
Code likes this (one) :
altlvds_tx altlvds_tx_u(.tx_in(a), .tx_inclk(clk), .tx_enalbe(load_en), .tx_out(tx_out));
altiobuf altiobuf_u(.data_in(tx_out), .oe(1'b1), .data_out(tx_out_o));
altiobuf altiobuf_u1(.data_in(tx_out),.oe(1'b1),.data_out(tx_out_n));
assign tx_out_n_o = ~tx_out_n;
SDC like this:
set_instance_assignment -name IO_STANDARD LVDS_E_3R -to tx_out_o
set_instance_assignment -name IO_STANDARN LVDS_E_3R -to tx_out_n_o
set_location_assignment PIN_A23 -to "tx_out_o"
set_location_assignment PIN_A24 -to "tx_out_n_o" (assuming A23 and A24 for DIFFIO_RX)
this method has error when I compile code.
the code (two):
altlvds_tx altlvds_tx_u(.tx_in(a), .tx_inclk(clk), .tx_enalbe(load_en), .tx_out(tx_out));
altiobuf altiobuf_u(.data_in(tx_out), .oe(1'b1), .data_out(tx_out_o), .data_out_b(tx_out_n_o));
SDC like this:
set_instance_assignment -name IO_STANDARD LVDS_E_3R -to tx_out_o
set_location_assignment PIN_A23 -to "tx_out_o"
# set_location_assignment PIN_A24 -to "tx_out_n_o" (assuming A23 and A24 for DIFFIO_RX)
this method has error when I compile code.
the code (three)
altlvds_tx altlvds_tx_u(.tx_in(a), .tx_inclk(clk), .tx_enalbe(load_en), .tx_out(tx_out));
altiobuf altiobuf_u(.data_in(tx_out), .oe(1'b1), .data_out(tx_out_o));
altiobuf altiobuf_u1(.data_in(tx_out),.oe(1'b1),.data_out(tx_out_n));
assign tx_out_n_o = ~tx_out_n;
SDC like this:
# set_instance_assignment -name IO_STANDARD LVDS_E_3R -to tx_out_o
#set_instance_assignment -name IO_STANDARN LVDS_E_3R -to tx_out_n_o
set_location_assignment PIN_A23 -to "tx_out_o"
set_location_assignment PIN_A24 -to "tx_out_n_o" (assuming A23 and A24 for DIFFIO_RX)
this method has error when I compile code.
So I don't know how to implement it , and I can not find one example and have no idea. I need help to resolve this problem. Can you help me?
Thanks,
Lambert
Frequent ContributorHi Lambert,
To be frank, I did not done an design with Altera LVDS block and Altiobuff. So I am not in a position to commend on the use case . One more thing I notices is that the file mentioned is SDC file, Can you please assign the above statement in qsf file.
Occasional ContributorHi RSree,
I think the problem does not depend on the file of pins assignments, and I think I face some special thing which needs to do when implement Emulated output buffer, if you have one simple case which you implementa the Emulated output buffer, it may give me a hand and let me find the error. Because I have no example to do this thing though I have serched for many files and website. There is less tips in Handbook.
Best regards,
Lambert
Frequent ContributorHi Lambert,
From my side, I do not have any reference design
